Study links LUTs to CKD in under-75s

Researchers have found a ‘strong association' between the presence of lower urinary tract symptoms and chronic kidney disease among men under 75.

The researchers believe that further studies could establish a causal link, which would challenge NICE guidance recommending testing of renal function in patients with LUTs only when there are clinical indicators.

Professor Simon de Lusignan, a GP in Guildford, was part of the research team that collected data on patients with LUTs and CKD from more than a million patients at 127 UK practices.

He said a man under 75 with LUTS was 3.68 times more likely to have CKD than a man under 75 without LUTS. But there appeared to be no significant association between LUTs and CKD among men over 75, he added.

LUTs are known to be associated with bladder outflow obstruction including benign prostatic hyperplasia (BPH), and 15-30% of patients with BPH undergoing prostatectomy have impaired renal function. But the precise relationship between the two is not known.

Professor de Lusignan, professor of primary care and clinical informatics at the University of Surrey, said: ‘The association between LUTs and CKD is new and currently unreported.

‘While this study has all the usual limitations in working with routine data, particularly missing data, the association between LUTs and CKD is strong.

‘If the strength of this association is repeated in other studies and a causal link found, recommendation may change about the need to test renal function in people with LUTs.'

Professor Mike Kirby, a GP in Letchworth, Hertfordshire, who has an interest in CKD, said he routinely gives LUTs patients an estimated eGFR test to investigate kidney function.

‘It's important to do this because CKD will be progressive if you don't get control of the blood pressure and reduce protein loss,' said Professor Kirby.

A link between LUTs and CKD is plausible because there are common features across the two conditions, including high blood pressure and abnormal blood sugar levels, he added.